Rubber flooring products are usually made from sulphur cured SBR (Styrene-Butadiene Rubber) and are not heat stable at processing and curing temperatures; this yields to discoloration and makes it difficult to control color shading within the same production run, and also from run to run. Flooring products made from NR (Natural Rubber) or NBR (Nitrile-Butadiene Rubber), or a blend thereof, suffer from similar problems. These problems present major issues for flooring products because aesthetic attributes can be as important to customers as are physical attributes.
A standard formula for a traditional rubber flooring product is as follows:                Rubber (SBR, NR, NBR, or a blend of): 20-50%        Fillers (clay, silica, limestone, or a blend of): 40-70%        Plasticizer/Resin: 2-10%        Vulcanisation package: 2-10%        